get a weight distrution hitch you running stock gears i hope not cause your tranny is going to hate you if so ask me how i know xjs are rated for lb tongue weight wo distribution hitch and lb with thats not just for your rear axle its a rating for your transmission too most xjs came from the factory with a class ii hitch tow packages came with class iii tow springs and gears so if your running stock gears on big tires chances are there is going to be a big chance of a tranny rebuildreplacement in your near future